Stroke is a major cause of disability including memory impairment. Our laboratory has shown that a novel treatment, anti-Nogo-A immunotherapy results in sensorimotor functional recovery after stroke in rodents. However, the role of anti-Nogo-A immunotherapy in memory recovery after stroke has not, as of yet, been investigated. The purpose of this proposal is to investigate anti-Nogo-A immunotherapy as a therapeutic intervention to improve memory impairment after stroke in aged rodents. Aim 1 will employ the Morris water maze to determine whether anti-Nogo-A immunotherapy after stroke in the aged attenuates memory impairment. The Morris water maze will be used to evaluate spatial reference and working memory. Aim 2 will employ Golgi-Cox analysis to determine whether anti-Nogo-A immunotherapy after stroke induces dendritic plasticity in the hippocampus and entorhinal cortex, two brain structures involved in learning and memory. Neurons in the hippocampus (CA1 pyramidal cells, CAS pyramidal cells, and DG granule cells) and entorhinal cortex (layer II stellate cells, layer III pyramidal cells, and layer V pyramidal cells) of Golgi-Cox processed brains will be examined for structural neuronal plasticity by quantification of dendritic arborization, spine density, and spine morphology. These experiments are relevant to clinical practice by addressing the significant decrease in quality of life caused by memory impairment after stroke. In addition, the translational relevance of these experiments is maximized by modeling the elderly human population, in which stroke is most prevalent, with aged rodents. Furthermore, anti-Nogo-A immunotherapy is a promising therapeutic intervention that may be quickly translated into a clinical trial for stroke. This is evidenced by the Phase 1 clinical trial that has begun in Europe to test anti-Nogo-A as a therapeutic intervention for spinal cord injury. Stroke is a major cause of disability in the United States and in many cases the disability is contributed to by cognitive impairments including memory impairments. This proposal will contribute to the development of treatments for cognitive impairments including memory impairments after stroke. In addition, this proposal will lead to important information regarding the role of neuronal plasticity in brain repair after stroke.